Pen holder



FIG. 1 shows a perspective view;

FIG. 2 shows a top view;

FIG. 3 shows a front view;

FIG. 4 shows a side view; and,

FIG. 5 shows a bottom view.

The suspension loop and writing instrument depicted by means of broken lines in FIG. 1 have been shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a pen holder, as shown and described. 